/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.replica.replicaisland;

/**
 * ObjectManagers are "group nodes" in the game graph. They contain child
 * objects, and updating an object manager invokes update on its children.
 * ObjectManagers themselves are derived from BaseObject, so they may be strung
 * together into a hierarchy of objects. ObjectManager may be specialized to
 * implement special types of traversals (e.g. PhasedObjectManager sorts its
 * children).
 */
public class ObjectManager extends BaseObject {
	protected static final int DEFAULT_ARRAY_SIZE = 64;

	private FixedSizeArray<BaseObject> mObjects;
	private FixedSizeArray<BaseObject> mPendingAdditions;
	private FixedSizeArray<BaseObject> mPendingRemovals;

	public ObjectManager() {
		super();
		mObjects = new FixedSizeArray<BaseObject>(DEFAULT_ARRAY_SIZE);
		mPendingAdditions = new FixedSizeArray<BaseObject>(DEFAULT_ARRAY_SIZE);
		mPendingRemovals = new FixedSizeArray<BaseObject>(DEFAULT_ARRAY_SIZE);
	}

	public ObjectManager(int arraySize) {
		super();
		mObjects = new FixedSizeArray<BaseObject>(arraySize);
		mPendingAdditions = new FixedSizeArray<BaseObject>(arraySize);
		mPendingRemovals = new FixedSizeArray<BaseObject>(arraySize);
	}

	@Override
	public void reset() {
		commitUpdates();
		final int count = mObjects.getCount();
		for (int i = 0; i < count; i++) {
			BaseObject object = mObjects.get(i);
			object.reset();
		}
	}

	public void commitUpdates() {
		final int additionCount = mPendingAdditions.getCount();
		if (additionCount > 0) {
			final Object[] additionsArray = mPendingAdditions.getArray();
			for (int i = 0; i < additionCount; i++) {
				BaseObject object = (BaseObject) additionsArray[i];
				mObjects.add(object);
			}
			mPendingAdditions.clear();
		}

		final int removalCount = mPendingRemovals.getCount();
		if (removalCount > 0) {
			final Object[] removalsArray = mPendingRemovals.getArray();

			for (int i = 0; i < removalCount; i++) {
				BaseObject object = (BaseObject) removalsArray[i];
				mObjects.remove(object, true);
			}
			mPendingRemovals.clear();
		}
	}

	@Override
	public void update(float timeDelta, BaseObject parent) {
		commitUpdates();
		final int count = mObjects.getCount();
		if (count > 0) {
			final Object[] objectArray = mObjects.getArray();
			for (int i = 0; i < count; i++) {
				BaseObject object = (BaseObject) objectArray[i];
				object.update(timeDelta, this);
			}
		}
	}

	public final FixedSizeArray<BaseObject> getObjects() {
		return mObjects;
	}

	public final int getCount() {
		return mObjects.getCount();
	}

	/** Returns the count after the next commitUpdates() is called. */
	public final int getConcreteCount() {
		return mObjects.getCount() + mPendingAdditions.getCount()
				- mPendingRemovals.getCount();
	}

	public final BaseObject get(int index) {
		return mObjects.get(index);
	}

	public void add(BaseObject object) {
		mPendingAdditions.add(object);
	}

	public void remove(BaseObject object) {
		mPendingRemovals.add(object);
	}

	public void removeAll() {
		final int count = mObjects.getCount();
		final Object[] objectArray = mObjects.getArray();
		for (int i = 0; i < count; i++) {
			mPendingRemovals.add((BaseObject) objectArray[i]);
		}
		mPendingAdditions.clear();
	}

	/**
	 * Finds a child object by its type. Note that this may invoke the class
	 * loader and therefore may be slow.
	 * 
	 * @param classObject
	 *            The class type to search for (e.g. BaseObject.class).
	 * @return
	 */
	public <T> T findByClass(Class<T> classObject) {
		T object = null;
		final int count = mObjects.getCount();
		for (int i = 0; i < count; i++) {
			BaseObject currentObject = mObjects.get(i);
			if (currentObject.getClass() == classObject) {
				object = classObject.cast(currentObject);
				break;
			}
		}
		return object;
	}

	protected FixedSizeArray<BaseObject> getPendingObjects() {
		return mPendingAdditions;
	}

}
